Apparatus for electrically isolating a portion of the atria

ABSTRACT

Devices for insertion into an atrial appendage of stasis reducing components such as mesh members, chemical bonding agents or expandable anchors are disclosed.

This application is a continuation of U.S. application Ser. No.09/524,263, filed Mar. 13, 2000, now U.S. Pat. No. 6,379,366, which is acontinuation of U.S. application Ser. No. 08/483,991, filed Jun. 7,1995, now U.S. Patent No. 6,132,438.

FIELD OF THE INVENTION

This invention relates to the reduction of regions of blood stasis andultimately thrombus formation in such regions, particularly in theatrial appendages for patients with atrial fibrillation. Morespecifically, the invention relates to procedures and devices foraffixing the atrial appendages in an orientation that reduces subsequentformation of thrombus.

BACKGROUND OF THE INVENTION

The atria must enable organized electrical propagation from the SA Nodeto the AV Node to stimulate the atria to contract in an organized way totransport blood from the atria to the ventricles, and to provide timedstimulation of the ventricles. The atrial appendages are especiallyimportant in the transport of blood because they have a sack-likegeometry with a neck potentially more narrow than the pouch. In thiscase, contraction of the appendage is essential to maintain an averageabsolute blood velocity high enough to eliminate potential stasisregions which may lead to thrombus formation.

Atrial fibrillation and abnormalities which may lead to atrialfibrillation (such as mitral and/or tricuspid regurgitation) are oftenassociated with abnormal electrical propagation through the heartleading to inefficient transport of blood in certain regions of theatria, and/or an enlargement of one or both atria to up to 2-3 times thenormal size.

Heretofore, atrial fibrillation has often been treated either byadministration of drugs or through surgical procedures, for example,procedures which surgically create a maze pattern in the atria whichreduces the probability of fibrillation. The typical access points intothe interior of the atria during a surgical procedure are the atrialappendages. Therefore, at the conclusion of the surgical procedure, theregion occupied by the atrial appendages is eliminated by surgicallyremoving the appendages. This mitigates subsequent problems resultingfrom blood stasis in the atrial appendages as well as from electricalisolation of the appendages from the rest of the atria.

More recently, maze-like procedures have been developed utilizingcatheters which may create long thin lesions to effectively create amaze for electrical conduction in a predetermined path. However, suchminimally invasive procedures may result in regions of continued bloodstasis, particularly in the atrial appendages due to electricalisolation of the appendages or decreased contractility of the tissue dueto the destruction of large regions of atrial tissue. Also, the responseof the atria to permanent conversion from atrial fibrillation to sinusrhythm after a catheter-based and/or surgical maze procedure has notbeen proven to return appendage function to normal.

Since such catheterization procedures do not admit themselves tosurgical removal of the appendages, a need has developed for proceduresand devices which reduce stasis regions to effectively minimizesubsequent thrombus formation within the appendages. Specifically,procedures and devices which reposition the atrial appendages and affixthem in the altered position to reduce stasis regions and ultimatelythrombus formation would be desirable.

SUMMARY OF THE INVENTION

An important aspect of the invention involves providing methods anddevices to reposition the atrial appendages, for example by inversionthereof either totally or partially. In accordance with this aspect ofthe invention, several embodiments of devices are provided for grabbingor otherwise attaching themselves to an appendage wall and eitherinverting or otherwise pulling the walls of the appendage together toreduce the size of the region of potential blood stasis, andconsequently the volume of the affected atrium. In accordance with thisaspect, it is an object of the invention to reduce the region ofpotentially static blood and, hence the thrombogenicity of the atrium.

In accordance with one embodiment addressing this aspect of theinvention, a device is provided which uses a distal helical coil topenetrate the appendage wall and, thus, provide an attachment forpulling the appendage inwardly into the atrium. In accordance with afurther, alternative, embodiment, a multi-pronged grabbing device isprovided on the distal end of a catheter which enables grabbing of theappendage surface with the prongs for pulling on the walls to cause aninversion thereof and/or to reduce atrial volume. In accordance with astill further alternative embodiment, a device is provided whichperforates the appendage wall and then this, or another member isinserted to expand on the exterior appendage wall surface, therebyanchoring the catheter to the appendage wall so that the wall may bepulled into the atrium.

Another important aspect of the invention involves methods and devicesfor affixing the appendages in a predetermined position for permanentreduction of potential stasis regions. In accordance with one embodimentaddressing this aspect of the invention, the appendages are chemicallybonded in a predetermined position such as the inverted position. Inaccordance with this aspect of the invention, it is preferred that abiocompatible chemical bonding agent be introduced into the area outsideof the appendages to chemically bond them in position, without bondingthe epicardial surface of the atria to the pericardium. In accordancewith this constraint, the chemical bonding can be assisted by utilizingan encircling tying means which may either be formed of a materialdesigned to permanently stay in place around the appendage or,alternatively, which may be a temporary support structure formaintaining the appendage's shape during the affixing process.

Further, in accordance with this aspect of the invention, alternativedevices are provided for introduction of chemical bonding agents intothe area outside of the appendage epicardium. In accordance with onesuch embodiment, a helical grasping device is provided which uses ahollow helical coil, which thereby provides a lumen for injecting abonding agent therethrough after the appendage wall has been penetratedby the helical device.

In accordance with an alternative embodiment related to this aspect, aseparate probe is provided for introduction of a chemical bonding agent.The separate probe may take the form of a sharply pointed elongatedhollow tubular canula which forms an injection port separate from theappendage surface grasping device.

In accordance with yet another alternative embodiment addressing thisaspect of the invention, several alternative devices and procedures formechanically fixing the appendages in a desired orientation areprovided. In accordance with one such embodiment of the invention, anappendage encircling lasso device is utilized to encircle and affix theappendages into the desired orientation. In accordance with a relatedalternative embodiment, the lasso device may be of the zip-tie typewhich utilizes a ratcheting mechanism on the surface of the encirclingmaterial so that the lasso is of the type that can be tightened butcannot loosen once affixed in the tightened position. In accordance witha still further alternative embodiment addressing this aspect of theinvention, a pre-shaped memory elastic material such as nickel titaniumor a similar material may be introduced around or into the appendage andallowed to resume its shape either by elastic memory or temperaturetransition memory to thereby affix the position of the invertedappendage. Such devices may either be pre-shaped to encircle theinverted appendage or may be extended through the appendage walls tomechanically affix them together.

In accordance with yet another procedure for affixing the appendagewalls together, there is provided a catheter having RF energy emittingelectrodes which can thermally fuse the inverted appendage wallstogether.

In accordance with a still further alternate embodiment, a device suchas a nitinol mesh is introduced into the atrial appendage interiorwithout inversion thereof in order to form a reinforcement for anchoringthrombi in position where collagen may accumulate to fill the appendagewith natural materials which are thus anchored in place so that they donot enter the bloodstream.

In accordance with a yet further embodiment of the invention, a suturematerial may be secured to the appendage walls, in an arrangementresembling a purse drawstring, which can be pulled together to compressthe appendage walls against each other into a tightened sack where thepouch of the appendage is effectively separated from the blood pool ofthe atrium.

Further objects and advantages of the invention will become apparentfrom the following detailed description, the claims and the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary view, with parts in section, illustratingintroduction of a catheter into the right atrium of a heart inaccordance with the invention;

FIG. 2 is a fragmentary view, with parts in section, showingintroduction of a catheter into the right atrium of the heart via thefemoral vein;

FIG. 3 is a fragmentary view showing the right atrium with the catheterintroduced therein and with the right atrial appendage inverted;

FIG. 4 is a fragmentary view of the left atrium, with parts in section,illustrating introduction of a catheter into the left atrial appendagevia a retrograde procedure;

FIG. 5 is a fragmentary view, with parts in section, showing positioningof a catheter on the endocardial surface of a left atrial appendageusing a transeptal procedure;

FIG. 6 shows introduction of a catheter via a transeptal approach forinversion of the left atrial appendage;

FIG. 7 is a side view illustrating a helical coil attaching catheterused in connection with the invention;

FIG. 8 is a sectional view illustrating a helical coil catheter with anindependently rotatable hollow coil assembly with a lumen extendingtherethrough;

FIG. 9 is a sectional view showing the insertion of the helical coilcatheter in FIG. 7 into the myocardium to provide a focal point forpulling the appendage;

FIG. 10 illustrates the inversion of the appendage wall shown in FIG. 9utilizing the catheter helical coil assembly shown in FIG. 7;

FIG. 11 is a fragmentary view showing the introduction through thehelical coil assembly of FIG. 7 of a marking contrast material;

FIG. 12A is a sectional view of a catheter distal tip employing a threeprong attaching catheter;

FIG. 12B is a sectional view of a catheter similar to that shown in FIG.12A except that the prongs extend radially outward;

FIG. 13 is a fragmentary view illustrating attachment of the catheter ofFIG. 12A to an appendage wall;

FIG. 14 is a fragmentary view illustrating use of the catheter of FIG.12A for inversion of an appendage wall;

FIG. 15 is a fragmentary view of the distal tip of the catheter of FIG.12A retracted into a protective sheath;

FIG. 16A is a fragmentary side view of a catheter distal sectionillustrating a hollow needle incorporating an internal extending,expandable type attachment/pulling element;

FIG. 16B is a side view of the attachment/pulling element of FIG. 16A inan expanded configuration;

FIG. 17 is a fragmentary view illustrating another attachment/pullingelement configuration which may be used to provide an attachment pointwith which to invert an atrial appendage;

FIG. 18 is a fragmentary view showing a catheter distal tip carrying acompound loop device;

FIG. 19A illustrates an inverting catheter used in conjunction with acompound loop support catheter;

FIG. 19B is a fragmentary side view illustrating the inversion of anatrial appendage utilizing the devices shown in FIG. 19A;

FIG. 20 is a fragmentary side view showing the use of a graspingcatheter of the general type shown in FIG. 12A in conjunction with alasso catheter for maintaining the walls of the inverted appendagetogether;

FIGS. 21 and 22A are fragmentary views of the combination shown in FIG.20 illustrating further steps of tying the appendages in an invertedorientation;

FIG. 22B is a schematic showing one embodiment of a tying mechanism foruse in the lasso catheter of FIGS. 20-22A;

FIGS. 23 and 24A are fragmentary views illustrating the use of acatheter of the general type shown in FIG. 7 in conjunction with areleasable lasso catheter and showing the introduction of abiocompatible adhesive/filler material into the space outside of theinverted appendage;

FIG. 24B is a fragmentary view showing the withdrawal of a catheter ofthe type shown in FIG. 7 after affixing in place an inverted appendagewith a stabilizing filler material;

FIG. 25 is a fragmentary sectional view showing a catheter with dualinfusion ports for introduction of fluid materials;

FIG. 26 is a fragmentary view showing the use of a further embodiment ofa lasso catheter, which is made of a metallic coil or other electricalconductor and is connected to an RF Generator for use in thermallyfusing the appendage walls;

FIG. 27A is a fragmentary view showing the application over an invertedappendage of a metallic mesh;

FIGS. 27B and 27C are fragmentary sectional views of a cathetermechanism used to expand the metallic mesh during insertion over theinverted appendage;

FIG. 28 is a fragmentary sectional view showing the insertion of ahelical metallic winding made from a memory transitional material whichupon introduction through the appendage expands or contracts to itsoriginal form at body temperature and holds the appendage in place;

FIG. 29 is a sectional view of a catheter containing an expandableanchor for insertion into an inverted appendage;

FIG. 30 is a cross-sectional view taken along 30—30 of FIG. 29;

FIG. 31A is a cross-sectional view of an appendage showing the use ofinsertable expandable anchors in conjunction with a draw string;

FIG. 31B is a cross-sectional view showing the appendage of FIG. 31Aafter it has been drawn together;

FIG. 31C is a cross-sectional view showing a single expandable anchorinserted into an appendage wall;

FIG. 32A is a sectional view of a catheter containing an alternativetype of expandable anchor for insertion into an inverted appendage;

FIG. 32B is a cross-sectional view showing a single expandable anchor ofthe type shown in FIG. 32A inserted into an appendage wall;

FIG. 33A is a side view of a handle mechanism for a catheter with afixed hollow needle and an access point for an internal styletmechanism;

FIG. 33B is a side view of a handle mechanism for a catheter with amoveable hollow needle and an access point for an internal styletmechanism;

FIG. 34 is a fragmentary view, with parts in section, illustratingintroduction of a catheter into pericardium by means of a thoracostomyin accordance with the invention; and,

FIG. 35 is an enlarged fragmentary view, with parts in section, of oneembodiment of a catheter usable in the procedure shown in FIG. 34.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Referring more specifically to the drawings, FIGS. 1-3 show, infragmentary fashion, the right atrium 10, the superior vena cava 12, theinferior vena cava 13, the ascending aorta 14, the right atrialappendage 16, the membranous septum 18, the right atrial freewall 20,the tricuspid valve 22, the opening of the coronary sinus 24, the valveof the coronary sinus 26, and the fossa ovalis 28.

A left atrium 11 is shown in FIGS. 4-6. There are also seen therein theaortic valve 15, the left atrial appendage 17, the left superiorpulmonary vein 19, the mitral valve 21, and the left ventricle 32.

A catheter 40 is shown generally being introduced into the atria of aheart through various cardiovascular introduction passageways as will bediscussed hereinafter. The point of attachment of catheter 40 to thewall of an atrial appendage 16 or 17 is indicated generally at 42.

Referring to FIGS. 1-6, various ways of entering a heart chamber andpositioning a catheter tip on the interior wall of the atrial appendagesare illustrated. In FIG. 1, a catheter 40 is shown being advancedthrough the jugular vein past the superior vena cava 12 and into theright atrium 10 where it is steered so the tip is positioned on theendocardial surface of the right atrial appendage 16 where attachment ismade. FIG. 2 illustrates a procedure for introducing the catheter 40through the femoral vein into the right atrium 10 and then into theright atrial appendage 16. FIG. 3 illustrates the inversion of the rightatrial appendage 16 using the catheter 40 introduced as shown in FIG. 2.

FIG. 4 illustrates the positioning of a catheter distal tip at a point42 on the endocardial surface of the left atrial appendage 17 utilizinga retrograde procedure. A sheath with a preformed configuration may berequired to maneuver the catheter tip down through the aorta 14 and upthrough the mitral valve 21. In addition, such a sheath would provideadditional support for maneuvering the tip of the catheter. FIG. 5 showspositioning of a catheter tip at a point 42 on the endocardial surfaceof the left atrial appendage 17 utilizing a transeptal introduction.Transeptal introduction is achieved by inserting an introducer or sheathwith an internal dilator through the femoral or jugular vein and intothe interior of the right atrium. Once in the right atrium, a longhollow needle with a preformed curve and a sharpened distal tip isintroduced through the dilator and is forcibly inserted through thefossa ovalis 28. A radiopaque contrast material is injected through theneedle to ensure the needle is in the left atrium as opposed to being inthe pericardial space, aorta, or other undesired location. Once theposition of the needle in the left atrium is confirmed, the dilator andsheath are advanced over the needle and into the left atrium. Then, theneedle and dilator are removed leaving the sheath as an access point tothe left atrium. FIG. 6 shows the inversion of the left atrial appendage17 after catheter 40 has been attached at point 42 and by using atranseptal approach as shown in FIG. 5. The use of such delivery systemsas sheaths is shown in pending U.S. application Ser. No. 08/136,218,filed Oct. 14, 1993, and entitled “Cardiac Mapping and AblationSystems.”

Methods & Devices for Repositioning Appendage Walls

Referring now to FIGS. 7-11, there is seen one type of catheter 50provided for attachment of the distal tip thereof to the wall of anatrial appendage 16 or 17. The catheter 50 includes a catheter body 52having a distal tip portion 54. In this embodiment a hollow coil 58 isattached to the catheter distal tip 54 and has a lumen 55 extending fromthe proximal end of the coil at the distal tip attachment point to thecatheter handle assembly (not shown), The coil 58 is rotated by torquingthe catheter body 52. The catheter body 52 may be provided with asteering mechanism 57, for example, of the type shown in Lundquist andThompson U.S. Pat. No. 5,254,088, which is incorporated herein byreference.

In the embodiment shown in FIG. 8 the distal tip portion 54 of thecatheter 50 is provided with an opening 56 through which the helicallycoiled distal tip element 58 can be advanced by rotation. Upon rotationof an inner supporting member 59 relative to catheter body 52, thedistal helical tip portion 58 is rotated into the wall of atrialappendage 16 or 17. This opening 56 may constitute a single isolatedhole which fits only the outer diameter of the helical coil assembly ora larger hole in the distal portion of the tip. An isolated holeprovides support for the helical coil assembly during advancement andwithdrawal as well as providing a blunt surface masking the sharp distaltip needle 58 during manipulation of the catheter through thevasculature.

As shown in FIG. 7, the helical coil may alternatively be permanentlyattached to the distal tip of the catheter thus requiring rotation ofthe catheter body 52 to screw the helical coil into or out of thetissue.

The distal tip of the helical element 58 is sharpened so that it has thecapability of impaling the tissue wall. The rotatable supporting member59 constitutes separate torque assembly that can be rotated manuallyfrom a point outside the body to cause rotation of element 59 relativeto the catheter body 52. This rotatable supporting member may be made ofbraided composite assembly such as stainless steel braid with polyamide,or a slotted hollow tube with an outer layer of shrink tubing. Once thehelical coil assembly 58 is screwed into the appendage 16 or 17, theappendage may be pulled into the inverted position by applying pullingforces to the catheter body 52.

Since the distal helical member 58 is preferably hollow and attached toa tube with an internal lumen passing from the distal tip to the handleassembly, radiopaque contrast material 60 may be injected to detect thelocation of the distal tip of catheter 50 using, for example,fluoroscopy. This is important so as to ensure that the distal end ofthe helical coil needle 58 is in the pericardial space and has notperforated the pericardium 53 as shown in FIG. 11. In addition, thehelical coil assembly and/or the distal catheter tip may be radiopaque.

Alternatively, an echoluscient material may be injected to locate thedistal tip using transthoracic, transesophageal, and/or intracardiacechocardiography. Also, transponders may be attached to the helical coilassembly for locating thereof by echocardiography.

The hollow lumen 55 in the distal helical member 58 can also be used forintroduction of an adhesive or bonding material therethrough as will befurther set forth hereinafter.

Referring to FIGS. 12-15, there is seen an alternative type of graspingcatheter 70 provided on a catheter body 52. The catheter tip 74 includesa plurality of grasping prongs 72 which are movable from an expandedposition to a retracted position as seen in FIGS. 13-14 for grasping thewall of the atrial appendage 16 or 17, so that pulling forces can beapplied for inversion thereof. Preferably, the pronged tips are enclosedin a tubular tip 74 which facilitates introduction of the catheterthrough the vasculature and into a heart chamber and subsequentwithdrawal thereof once the procedure is completed. Prongs 72 arepreferably mounted in a mounting block 76 in such a fashion that theyare biased toward the expanded position shown in FIGS. 12A and 13. Thisblock 76 is connected to a handle assembly through a stylet 62. As thestylet 62 is retracted at the handle, the block 76 is withdrawn intotubular tip 74; the prongs are caused to contact the interior surface ofthe tip 74 and move toward each other, thus impaling the surface of theappendage 16 or 17 as seen in FIG. 14. The prongs are provided withsharp distal ends to readily penetrate tissue and with a wide section atthe apex of the curvature to contact a larger amount of tissue thusforming a large surface with which to pull tissue. The appendage 16/17is then inverted by pulling the catheter body sufficiently to causeinversion. The prongs can subsequently be released by distal extensionof the stylet 62 and the block 76 thereby allowing the prongs to expandagain to the position shown in FIG. 13. After the prongs 72 arewithdrawn from the wall of appendage 16 or 17, they can be returned tothe compact position shown in FIG. 15 so the catheter may be withdrawnfrom the vasculature.

Alternatively, as shown in FIG. 12B, prongs 73 are provided which in theexpanded form extend radially outward. During introduction of thisembodiment into the appendage 16/17, the prongs 73 are collapsed into alow profile and once they have passed through the appendage wall 16/17or inside the myocardium, the stylet 62 and thereby the block 76 isextended, allowing the prongs 73 to expand from the low profilenecessary for insertion to a radiating outward profile which provides asurface with which to pull the appendage 16/17.

Yet another form of catheter attachment and pulling mechanism 80 isshown in FIGS. 16A, 16B and 17. In accordance with this embodiment, aradially expandable flexible member 82 is positioned within a hollowneedle 66 located inside the interior of the catheter body 52 and distaltip element 83. Member 82 is attached to stylet 62 which extends fromthe distal tip 83 to the handle assembly. Flexible member 82 may be madefrom a memory elastic material such nickel titanium or stainless steel17/7. More than one flexible member 82 may be attached to a stylet 62,if desired, to increase the surface provided for pulling on theappendage 16/17.

Externally operable control means, such as extendable/retractableproximal knobs, are provided for advancing the stylet 62 and hollowneedle 66 independently of one another. Preferably, the distal end ofthe hollow needle 66 is extended through the appendage 16/17 andaccesses the pericardial space. As previously described, a contrastmaterial may be injected to confirm the location of the distal tip ofhollow needle 66. Then, the stylet 62 is advanced thereby expelling theflexible member 82 and allowing it to expand from the position shown inFIG. 16A to that shown in FIG. 16B. The distal tip of the hollow needle66 is provided with a sharpened point suitable for penetration of theappendage wall 16/17 when the flexible member 82 is in the retractedposition. Then, after penetration of the wall 16 or 17, the flexiblemember 82 expands into its predetermined shape and the catheter isthereby attached to the wall as seen in FIG. 16B. In this position, asubstantial pulling force can be applied to the atrial appendage 16 or17 to cause inversion of the same.

The hollow needle 66 may be retracted into its retracted or restingposition in element 83 to minimize any damage the sharp distal needletip may cause while pulling the appendage 16/17. In addition, theflexible member 82 may be coiled at its distal end to preventperforation of the tissue especially that of the pericardium whilemanipulating the member 82 by means of stylet 62. In an alternativeembodiment, the member 82 can have a blunt end instead of a coiled tip.In FIGS. 16 & 17, the member 82 is attached to the stylet 62. Analternative configuration of the flexible member 82 (fully expanded) isshown in FIG. 17.

A number of additional shapes not shown in the FIGURES can function asmember 82. Any flexible self-expanding member or configuration which maybe extended into a low profile to fit inside a hollow needle or acatheter body and when extended beyond the distal end of theconstraining tube will expand, may be used to provide an attachmentpoint to pull the appendage 16/17 into an inverted position.

To retract the flexible member 82 from the attachment point 42, thesharpened hollow needle 66 is reinserted into the tissue to the proximalsurface of the tissue and the flexible member 82 is removed by pullingthe stylet 62. Thereafter, the hollow needle 66 and flexible member 82are positioned in their retracted positions so the catheter may besafely removed from the vasculature. The handle 64 shown in FIGS. 33Aand 33B can be used for this purpose. The rod 69 can be removed from theassembly shown in FIG. 33B and a stylet 62 and flexible member 82substituted therefor.

Methods & Devices for Affixing the Inverted Appendages

Referring to FIGS. 18, 19A and 19B, there is shown a compound loopassembly 77 carried on the distal end of a catheter 52. Loop assembly 77may be used as a support structure for pulling therethrough of appendage16 or 17. As seen in FIG. 18, assembly 77 is housed in an introducersheath 74A. An extendable/retractable support block 76A is manipulatedby extension and retraction of catheter body 52 relative to sheath 74A.A central opening 75 in support block 76A allows for introduction of aseparate attachment catheter, for example, catheter 70 through thecentral lumen of catheter 52. One or more supporting splines 78 areattached to block 76A and support another loop 79 which is of a sizeadapted to encircle the appendage 16/17 when inverted as shown in FIG.19B. In the embodiment of FIGS. 19A AND 19B, catheter 70 is introducedseparately from catheter 52.

This compound loop assembly 77 provides a support structure toappropriately deform the atrial appendage into a necked pouch tofacilitate subsequent attaching methods as described below. Any of theattaching catheters described above may be used in conjunction with thecompound loop structure. The compound loop catheter 77 may containmultiple loops to enable pulling of the appendage 16/17 into multiplesmall inverted sections of tissue instead of one larger invertedsection.

An alternative support structure, which may also be used itself to fixinverted appendage tissue in an altered position is shown in FIGS.20-22. Here there is seen the use of a dual catheter system including atying catheter 88 which inserts a lasso member 90 around a graspingcatheter 70, which is shown for purposes of illustration. In FIGS.20-22A, the appendage 16 or 17 is shown in the inverted position.Subsequently, the lasso member 90 is elevated around the invertedappendage 16 or 17 and thereafter tied by pulling the free end of thelasso member 90 by means of a stylet 62, which extends proximally into ahandle assembly. Lasso member 90 is thus formed into a tightenedconfiguration which holds and assists in moving the inverted appendage16 or 17 into the position shown in FIG. 22A.

FIG. 22B shows one embodiment of a lasso member 91 which has aratcheting mechanism to permanently tighten when the member 91 is pulledby the operator. In this case teeth 92 are adapted to slide through aslot 93 in a direction which allows tightening of the lasso, but doesnot allow loosening thereof. After the lasso member 91 has beentightened to maintain the position of the inverted appendage 16/17, thelasso member 91 is cut, leaving the tightened lasso in place. As seen inFIG. 22B, the lasso 91 is compressed to fit within an introducer sheath74 for introduction into the atrium. The lasso 91 is formed in a sizesufficient to encircle the inverted atrial appendage. As seen, slot 93is formed as a constriction between an anchoring member 94 and anopposed finger 98 which engages ratchet projections 92. Finger member 98as seen in FIG. 22B allows the ratchet projections to slide in adownward direction, but prevents them from moving upwardly. A cutter 100is provided to cut the lasso 91 loose from the catheter. Cutter 100 isactuated by pulling in a proximal direction on stylet 62. The back ofcutter 100 is contoured to slide over a projection 102 that causes thecutter to engage lasso 91 and force it against a backing member 103 sothat the sharpened tip of cutter 100 will sever the lasso 91. Afterlasso 91 has been severed, the anchor member 94 remains with the lassoand is disconnected from the catheter body 105 by rotation of thecatheter body to disconnect a threaded connection as shown. A retainingring 104 holds the cutter and backing member in place centrally withinthe catheter body 105.

An alternative embodiment for attaching the appendage 16/17 uses aninverting catheter described above and the tying catheter 88 with alasso member 90 previously described via a thoracostomy. The probesystem is inserted through an opening made in the intercostal space ofthe rib cage and advanced through the pericardium where it contacts theappendage 16/17. The inverting catheter is attached to the distal end ofthe appendage 16/17 with techniques previously described and is pulledso as to stretch the appendage structure 16/17 away from the main bodyof the atrium. Then, the lasso member 90 is wrapped over the stretchedappendage 16/17 as far toward the main atrial body as possible. Thelasso member 90 or 91 is subsequently tightened using techniquesdescribed above to isolate as much of the appendage 16/17 as possible.Subsequently, the appendage 16/17 may be cut and permanently removed byadvancing another probe with a cutting surface to cut the neck of theappendage pouch leaving the lasso member 90 or 91 holding the rest ofthe appendage in place. Additionally, the lasso member 90 or anothercauterizing probe may be used to fuse the appendage walls 16/17 togetheras will be described below for additional support after cutting off theappendage 16/17.

A further modified affixing embodiment is shown in FIGS. 23-24B. In thisembodiment, a helical coil catheter 50 as shown in FIG. 7 is used inconjunction with a lasso applying catheter 88 which applies a lassomember 90 around the inverted appendage 16 or 17. The hollow lumen ofthe helical distal end 58 of catheter 50 is used to infuse a chemicalfixing agent such as a cyanoacrylate 89, which after curing, affixes theinverted appendage 16 or 17 in the position shown in FIG. 25. While acyanoacrylate is the preferred adhesive used in conjunction with thisembodiment of the invention, other materials, for example other acrylatebased adhesives such as polymethyl methacrylate or other biocompatiblematerials can be substituted.

The catheter infusion lumen may have a Teflon® polytetrafluoroethylene(PTFE) or similar inert material surface inside to reduce the extent ofadhesive curing in the lumen prior to injecting the adhesive into thedesired region. Also, more than one lumen may be contained within thecatheter body to connect the helical coil hollow distal section to theinjection site at the handle. As seen in FIG. 25, separate lumens 48 and49 may be used to inject adhesive 89 and a contrast material to enablethe injection of either contrast material or adhesive into the desiredregion without needing to displace the dead volume of another materialfrom the lumen. Thus, one is able to quickly inject contrast at anypoint during the procedure to ensure the catheter has not moved whileinjecting the chemical adhesive. Also, an additional lumen may berequired to inject simultaneously a catalyst and an adhesive to enhancethe curing of the adhesive in the desired region. In FIG. 25 lumens 48and 49 both discharge into a enlarged area 47 in distal tip member 54A,which in the case of two part curable materials can be used to providefor mixing of the two components. The desired ratio of catalyst toadhesive for proper curing may be achieved by designing the ratio of therespective lumen diameters to match this ratio and controlling therespective infusion stylets to move simultaneously.

The infusion lumens are preferably formed by extruding a PTFE tube andbraiding a layer thereover of metal or polymeric plastic material.Thereafter and outer layer, preferably of a polyamide or polyesterpolymer is applied by dipping or extrusion.

After the adhesive material has solidified, the lasso member 90 may beexpanded free from the appendage walls 16/17 preferably by releasingbackward pressure on the retracting stylet 62 thus allowing the lassomember to loosen. Alternatively, an extending handle assembly may beactuated to open the lasso member 90 thereby loosening it. For thisapplication, lasso member 90 should not have a latching mechanism, asshown in a prior embodiment, 91, so it may be readily released upondemand. After loosening the lasso member 90, the catheters may beremoved from the vasculature.

Referring to FIG. 26, a releasable lasso member 142 may be manufacturedfrom electrical conductors such as platinum/iridium, gold, stainlesssteel, or other metallic coils or rings and may be attached throughelectrically conductive wires 141 traversing the catheter lumen 140 to aradiofrequency generator, such as the EPT-1000, which transmits currentat 500 kHz to the lasso member 142 to resistively heat the appendagewalls 16/17. This electrically isolates the appendage 16/17 to ensure noarhythmogenic fibrillation, tachycardia, and/or flutter originates fromthe trabeculated appendage. In addition, heating the appendage walls canthermally fuse the adjacent appendage walls together producing a bond tohold the appendage 16/17 in the inverted position. Alternatively,heating changes the structure of the tissue through desiccation tochange the shape of the appendage 16/17 even if a thermal bond ofadjacent walls is not achieved because the required bonding temperaturesare not reached. These changes in structure will help maintain theappendage 16/17 in the altered position. Of course, temperature sensorsplaced in the lasso member 142 may be used to regulate the heating tocontrollably ablate the appendage walls and/or thermally fuse adjacentwalls together. Devices usable for this purpose are shown in greater incommonly owned copending application Ser. No. 08/439,824 filed May 12,1995, the disclosure of which is incorporated by reference herein.

The composite loop structure 78 previously described may also be formedof an electrically conductive material and used to thermally heat and/orfuse the appendage 16/17 as described above.

Another method for affixing the appendage walls in an inverted oralternative position involves to insertion of an attachment member intoor over the appendage 16/17. This technique may be implemented whenattaching the appendage in an inverted position or pulling adjacentappendage walls together to produce a sack with the appendage pouchseparated from the atrium.

FIG. 27A illustrates a mesh 95 constructed from a memory elasticmaterial with temperature responsive transitional properties and/orsuperelastic properties, for example nickel titanium. Alteratively, aplastic material with elastic properties or stainless steel 17/7 may beutilized. The mesh 95 may be expanded over the inverted appendage withthe catheter 130 shown in FIGS. 27B and 27C. Alternatively, the mesh 95may be introduced into the pericardial space with a catheter of the typeshown in FIGS. 29 and 30. In this case, a sharpened hollow needle 66 isintroduced through the appendage wall 16/17 into the pericardial space.Then, a separately actuated stylet 62 is manually or automaticallyextended to insert the mesh attachment member 95 through the end of thehollow needle where it expands to its resting shape at body temperatureto maintain the appendage 16/17 in said shape.

Referring now to FIGS. 27A-C more particularly, there is seen anattaching catheter 50 which is sized to fit within an inner lumen 128located in mesh introducing catheter. The attaching catheter 50 and themesh introducing catheter 130 may be simultaneously introduced into theatrium. Alternatively, the attaching catheter 50 can be introduced intothe atrium and attached to an appendage wall 16-17. The introducercatheter 130 can then be guided over the appendage attaching catheter50. The mesh 95 is seen in its resting configuration in FIG. 27B.

Mesh 95 is supported within an introducer sheath 132 and on a base plateor cylinder 134 which is provided with an annular opening 136 to allowcatheter 50 to fit therethrough. Preferably, a retaining ring 138 isprovided to hold the wires 140 which may be, for example, in the form ofa suture or wire.

In use, catheter 130 is introduced over catheter 50 in the appendage16/17. The introducer sheath 132 and the retaining ring 138 and thus thepull wires 140 are retracted proximally forcing the distal end of themesh to expand radially. The expanding mesh 95 is then advanced over theinverted appendage 16/17. Subsequently, the wires 140 are released fromretaining ring 138 allowing the mesh 95 to close over the atrialappendage 16/17. The wires 140 are then retracted into sheath 132 andthe assembly is then removed from the vasculature.

Two alternative handle designs for the various catheters referred toabove are shown in FIGS. 33A and 33B. In FIG. 33A, a fixed introductiontube assembly 150 has an internal lumen 152 in which expandable anchorsand/or a stylet may be inserted. In FIG. 33B, the introduction tubeassembly 170 is axially moveable. In one embodiment, separate attachingand grasping catheters are used as a system. In an alternativeembodiment, a single catheter of the type shown in FIGS. 29 and 30 withan integrated grasping mechanism, such as a helical coil, may be used.

In FIG. 33A there is seen a typical catheter steering and manipulatingmechanism. Catheter body 52 having a distal tip portion 54 extendsdistally from a handle portion 64 which contains a steering handle 63 towhich steering wires 61 are attached to effect bending of steeringmechanism 57 remotely from handle 63. Conductive wires 65 may beincluded in the event that it is desired that, for example, a mappingelectrode be positioned on distal tip 54 to detect electrical activitywithin the heart.

The embodiment of FIG. 33A includes an expandable anchor introductionand/or push rod port 67 and a separate infusion port 68 through whichliquids can be introduced when needed in accordance with theabove-described procedures. A porous membrane or slotted hollow tube 71can be provided to allow flow of liquids from port 68 into the lumen ofintroducer port 67. In the embodiment shown in FIG. 33B, a push rod 69is included for the purpose of advancing expandable anchors or othercomponents introduced into the atrium in accordance with the invention.Advancing of rod 69 distally will advance the materials contained in theintroduction lumen 67 in a distal direction into the atrium. In thislatter embodiment the entire infusion assembly 150 is axially movable sothat the same can be advanced manually in order to effect tissuepenetration when required in accordance with the foregoing descriptions.

FIG. 28 shows a helical winding used as an attachment member 96 forholding the appendage 16/17 in place. The catheter shown in FIGS. 29 and30, and the handle assemblies shown in FIG. 33A or 33B may be used tointroduce the helical winding 96. The helical winding 96 is preferablymade from a memory elastic material as described above. The helicalwinding 96 is introduced in an extended shape which may easily be pushedinto the appendage walls 16/17 and after the helical winding 96 extendsbeyond the hollow needle 66 via extension of the stylet 62, the helicalwinding 96 expands into its resting shape holding the appendage 16/17.Alternatively, the helical winding 96 may be made from a stiffermaterial such as stainless steel 17/7 and screwed into the tissue.

FIG. 29 is a sectional view of a catheter which may insert the metallicmesh 95, the helical winding of FIG. 28, or other material with anelastic memory into or through the inverted appendage to maintain theappendage in the inverted position. FIG. 29 shows a catheter 110 havinga hollow needle distal tip portion 66 that contains an attachingexpandable anchor 116. The hollow needle is reciprocally fitted in adistal tip member 114 which has a central opening sized to allowreciprocation therein of the hollow needle 66. Distal tip 114 is securedby conventional means to a catheter body 112 within which is provided asteering mechanism 57 as described above. Also, fitted reciprocallywithin hollow needle 66 is a pushing stylet 118 which is utilized toexpel expandable anchor 116 after the proper location has been reachedthrough use of the sharp and hollow needle 66. After the tip has beenplaced in the desired position, the expandable anchor is expelled fromthe needle by extending stylet 118 and subsequently retracting thehollow needle 66 and the pushing stylet 118 within the rounded distaltip member 114.

Methods & Devices for Affixing Adjacent Appendage Walls

FIGS 31A-31C show a mechanism which creates a purse-string-likeconstriction around the interior surface of an appendage 16 or 17 (orother body cavity). This arrangement enables pulling of adjacent wallstogether, thus forming a tightened sack in which the pouch of theappendage is separated from the remainder of the atrium. Expandableanchors 116 of the type shown in FIG. 31C or expandable anchors 120shown in FIG. 32 may be introduced through the appendage wall 16/17 bymeans of a catheter similar to the one shown in FIG. 29. In such casemultiple expandable anchors 116 or 120 are placed within the hollowneedle 66 and are interconnected with a suture, wire, or similarmaterial 126. The suture 126 may be fed through a loop 117 in theexpandable anchor 116 to permit remote tightening of the appendage wallsafter all expandable anchors 116 have been placed or may be secured toeach of the expandable anchors 116 to tighten the walls 16/17 as theexpandable anchors are being placed. Ultimately, the appendage walls16/17 will be pulled together by the suture material 126 in the formshown in FIG. 31B. To separate the pouch from the atrium, a fillermaterial such as silicone or collagen may be inserted into the appendagepouch to fill the pouch and minimize or eliminate blood flow into or outof the pouch. Also, a memory elastic mesh 95 may be inserted into thepouch or over the sack entrance for additional support and to preventthrombus movement from the pouch into the atrium. Also, in thisembodiment, the blood inside the pouch will clot, forming a naturallyoccurring support structure for the separated appendage 16/17.

When the form of expandable anchors 120 of FIGS. 32A and 32B are used,suture material 126 may be continuously fed through a central lumen 124of pushing stylet 124 as shown.

Referring to FIGS. 34 and 35, there is seen a procedure for reducing thevolume of an appendage 16 or 17 by means of a thoracostomy. In thiscase, the pericardium is penetrated by means of an incision passingthrough the rib cage. The incision is entered by a grasping catheter,for example catheter 70 as already described hereinabove. Thereafter, alasso 90 or 91 can be utilized to tie off the neck of the appendage 16or 17 as seen in FIG. 34 utilizing a catheter 170 shown in FIG. 35. Theappendage can also be fixed in a repositioned location with reducedvolume by sutures, staples, memory wire, biocompatible adhesives, or bytissue ablation as described above.

As seen in FIG. 35, catheter 170 includes a flexible catheter body 172having a distal tip portion 174. A lumen or tubular guide 176 isprovided for allowing the lasso 90 to be freely axially movable so thatthe lasso 90 can be expanded or contracted. Also as seen in FIG. 35, thelasso 90 may have an enlarged end 8 for the purpose of anchoring thesame in catheter distal tip 174 as shown. Utilizing this arrangement,the appendage 16 or 17 can be permanently fixed in the altered positionutilizing staples, sutures, chemical bonding agents or by means ofablation. Alternatively, also a locking or ratcheting loop 91 of thetype described above can be permanently put in place to tie off the neckof the appendage 16 or 17.

It should be appreciated that the repositioning and affixing methods anddevices described above may apply to aneurysms, or any other bodycavities that naturally or pathologically exist.

What is claimed is:
 1. An apparatus for electrically isolating a portionof an atria, the atria including atrial walls having outer surfaces, theapparatus comprising: a handle; and an energy transmission structure,associated with the handle, including at least two energy transmissionsurfaces; the energy transmission structure being configured anddimensioned such that it is movable between a first orientation where adistance between the at least two energy transmission surfaces issufficient to accommodate at least two atrial walls that substantiallyoppose one another and a second orientation where the distance betweenthe at least two energy transmission surfaces will cause the at leasttwo atrial walls to be in contact with one another.
 2. An apparatus asclaimed in claim 1, wherein the energy transmission structure comprisesa releasable lasso.
 3. An apparatus as claimed in claim 1, wherein themission surfaces comprise ablation surfaces.
 4. An apparatus as claimedin claim 1, wherein the energy transmission surfaces compriseelectrically conductive material.
 5. An apparatus as claimed in claim 1,further comprising: a connector for connecting the energy transmissionsurfaces to an energy source.
 6. An apparatus as claimed in claim 1,wherein the energy transmission structure is configured and dimensionedsuch that the distance between the at least two energy transmissionsurfaces is sufficient to accommodate at least two atrial appendagewalls that substantially oppose one another when the energy transmissionstructure is in the first orientation and the distance between the atleast two energy transmission surfaces will cause the at least twoatrial appendage walls to be in contact with one another when the energytransmission structure is in the second orientation.
 7. An apparatus asclaimed in claim 1, wherein the at least two energy transmissionsurfaces are connected to one another, thereby defining a continuousenergy transmission surface.
 8. An apparatus as claimed in claim 1,wherein the energy transmission structure is configured and dimensionedsuch that the distance between the at least two energy transmissionsurfaces is sufficient to accommodate at least two left atrial wallsthat substantially oppose one another when the energy transmissionstructure is in the first orientation and the distance between the atleast two energy transmission surfaces will cause the at least two leftatrial walls to be in contact with one another when the energytransmission structure is in the second orientation.